Effects of manipulated palatability on appetite depend on restraint and disinhibition scores from the Three-Factor Eating Questionnaire.

OBJECTIVES: The present study evaluated the effects of dietary restraint on short-term appetite in response to manipulated palatability. DESIGN: The effects of palatability on appetite during a lunchtime meal were assessed by contrasting intake of a bland and palatable version of a simple food (within subject). To test how responses to palatability varied with restraint, these meals consumed by women were classified according to restraint (R) and disinhibition (D) scores from the Three-Factor Eating Questionnaire (TFEQ) as high R/high D (HR-HD), high R/low D (HR-LD), low R/high D (LR-HD) and low R/low D (LR-LD). SUBJECTS: A total of 40 normal-weight women subdivided into four groups based on TFEQ scores. MEASUREMENTS: The overall intake, appetite and hedonic ratings before, during and after the meal. RESULTS: All groups ate similar amounts of the bland food, but the LR-HD group ate significantly more of the palatable version than the other groups, whereas HR-LD did not increase intake in response to palatability. Hunger increased on tasting the palatable food in all but the HR-LD group, and this group ended both meals more hungry/less full than the others. CONCLUSION: Women classified as HR-LD were unresponsive to manipulated palatability, whereas those classified as LR-HD were over-responsive. These findings imply that some individuals are prone to over-respond to palatability and so are at greater risk of developing obesity, whereas others are able to resist the effects of palatability and so successfully self-restrict their food intake. Implications for obesity are discussed.

Acquisition and extinction of flavour preferences conditioned by caffeine in humans.

Previous research has shown that moderate caffeine users develop a liking for the flavour of a novel caffeinated drink only if they experience this drink in a caffeine-deprived state. This study tested how sensitive these conditioned-flavour preferences are to subsequent changes in deprivation state and the continued presence or absence of caffeine. Thirty-six moderate caffeine consumers were given 4 training days during which they evaluated a novel flavoured caffeinated drink consumed mid-morning after 12 h caffeine deprivation. Subjects were then divided into four groups depending on whether or not they remained caffeine-deprived and whether the test drink continued to contain caffeine. They then re-evaluated the novel drink over a further 4 test days. As expected, liking for the test drink increased across the 4 training days, and this increased liking was maintained across the 4 test days in the group who continued to receive the caffeinated version of the drink in a caffeine-deprived state. Liking decreased in the test phase in the caffeine-deprived group who no longer received caffeine (extinction). It is surprising that both groups who were tested in a non-deprived state showed a marked decrease in liking on all 4 test days relative to the last training day. This implies that conditioned-flavour preferences may not be expressed in the absence of the relevant motivational state (caffeine deprivation). Together, these data suggest that flavour preferences conditioned by caffeine are very sensitive to changes in the contingent relationship between deprivation state and caffeine content of the drink.